Stents and stent delivery systems are utilized in a number of medical procedures and situations. A stent typically is a prosthesis introduced via a catheter into a lumen of a body vessel in a configuration having a generally reduced diameter and then expanded to the diameter of the vessel. A stent delivery system includes a stent loaded onto the balloon of a balloon catheter. Stent delivery systems are commonly used during percutaneous transluminal coronary angioplasty (PTCA) procedures to deploy a stent inside a vessel proximate a lesion to support and reinforce the vessel walls while maintaining the vessel in an open, unobstructed condition.
Prior to use during a medical procedure, a stent is normally securely crimped onto the balloon of a balloon catheter. Stent crimping refers to reducing the cross-sectional dimensions or profile (e.g., the diameter) of a stent prior to use. Several techniques for crimping a stent onto a balloon of a balloon catheter have been developed. Some such crimping devices and methods are disclosed in U.S. Pat. Nos. 7,021,114, 6,920,674, 6,823,576, 6,387,118, 6,387,117, 6,360,577, and 5,992,000, the disclosures of which are incorporated herein by reference. However, in some instances these techniques have been found to result in the application of undesired uneven forces being applied to the stent and/or distortion of the desired cross-sectional shape of the stent, as well as other possible undesirable effects.
Therefore, it is desirable to develop stent crimping apparatus, assemblies and methods for more uniformly crimping a stent onto the balloon of a balloon catheter, while minimizing or eliminating distortion of the stent. For example, it may be desirable to generate iso-static forces acting on a stent during a crimping process. Additionally, it may be desirable to accommodate dissimilarities in the shape and/or regions of a stent (e.g., either circular/symmetrical stents and/or non-circular/non-symmetrical stents such as bifurcated stents) by optimally generating omni-directional forces, normal at all points of contact on the outer perimeter of the stent, during a crimping process.